The present invention relates to an internal-combustion engine including a lubricating oil circuit having a lubricating oil pump and an oil reservoir and further including a cooling oil circuit which is coupled to the lubricating oil circuit and which is supplied from the oil reservoir.
An internal-combustion engine of the above type is disclosed in German Offenlegungsschrift (Laid-Open Application) No. 2,609,844 wherein in an air-cooled internal-combustion engine in the hot regions of the cylinder heads at least one channel is provided in which the lubricating oil, functioning there as cooling oil, is driven by the oil pump. This measure takes into consideration the fact that in air-cooled internal-combustion engines, which in principle offer the advantage of a simple construction, there may occur high temperatures at least at certain locations. Such high temperatures are to be reduced by the additional oil cooling.
A significant feature of the prior art construction is the use of a single oil pump generating the flow of both the lubricating oil and the cooling oil. In view of the amount of energy required to drive the oil pump, this measure is justified if only individual regions of the engine are to be cooled by the oil.